Method of producing and maintaining a vacuum on a chamber



1 1 1a A w 0 a a i a v ii w FL? MW F. L. SHELOR METHOD OF PRODUCING ANDMAINTAINING A VACUUM ON A CHAMBER Filed March 7, 1932' A 2 J9 4/ 6 40 A*?%f a 4V Wfi 6' 3 ZJ y 2 PM 1 6 MW 6/ 6 j \./.,\@,r J 5,. g a\ufi 9 Wii. V 3:. a a 1 u 9U Q a g a 6 w z MW J J w mam w 4 Nov. 17, 1936.

0 2 N w MFW OOQJ =55 port9 andwithatapering Patented Nov. 17, 1936'ME'rno'n or PRODUCING ANn' MAINTAlN me A VACUUM ON A CHAMBER.

Frederick L. Shelor, Richmond, Va., assignor to Innovation Brakes, Inc.,Richmond, Va.,\ a corporation of Virginia Application March 7, 1932,Serial No. 597,359 2 Claims. (Cl. 188-152) The invention relates to newand useful improvements in the method of producing and maintaining avacuum on a chamber.

Anobject of the invention is to provide a method of creating a vacuum ona chamber of any'desired ratio relative to a vacuum creating meansoperating thereon withinthe limits of said I vacuum creating means, andfor maintaining substantially constant the degree of. vacuum on thechamber at the selected ratio.

In the drawing Figure 1 is a diagrammatic view Showing one form ofapparatus for carrying out the method;

Fig. 2 is a vertical sectional view through the A control valve fordeterminjng the degree of vacuum placed on the chamber and formaintaining the vacuum at the selected degree or ratio relative to thevacuum creating means, the valve being closed, and

Fig. 3 is a view similar to Fig. 2, showing the valve shifted to an openposition. v

The invention has to do with a method of creating avacuum on a chamber,which chamber is to be used in any desired way, such'for example,

' asthe applying of brakes to'a rotating part, in

which case one wall of the chamber will be made.

shiftable so that the difference in pressure between that on the chamberand atmospheric pres- ,sure may be utilized for forcing the brakingmember into contact with the rotating part. ,The chamber on which thevacuum is produced may be used as" a supply chamber for maintaining a.

predetermined'vacuum at various points in an apparatus of any type. v I

' 5 It is thought the method will be better understood by thedescription of the present illustrated --embodiment of an apparatus forcarrying out said method. In the drawing, a portion ofa chamber isdiagrammatically illustrated at l' and this is the chamber on whichfit avacuum of a predetermined degree. A chamber isdiagrammatically indicatedat 2 which may be the chamber of the pump of a vacuum creating means, ora chamber associated with the pump on which a vacuum is created ofsubstantially a predetermined degree, butby a greater degree than thatwhich it is desired to maintain on the chamber interposed b'etweenthetwochamhers is a control valve which includes a casing 3 having a pipe 4leading chamber l and a pipe 5 V V to the chamber 2 There is a pipe 6leading from the casing toa muflier isa sleeve 8. This sleeve 3 isprovided with a "port IS.

a point, and substantially V.-shaped in cross section, indicated at Hi.There is also a port ll and a similar recess l2 leading from one wallthereof. The sleeve is likewise provided with a This sleeve 8, as shownin the drawing, is connected to a lever l i pivoted at IE to .a bracketI6 and pivotally connected at l'l to an arm l8 at.- tached tothefsleeve. The lower end of the lever l4 carries a clamping screw l9shiftable in a slot 10 .20, in a bracket arm 2|. This provides a means 1whereby the lever l4 may be shifted to diiferent set positions andsecured in a set position.

Within the sleeve 8 is-a' cylindrical member 22 provided with a centralchamber 23. There is a port 24 leading outwardly from this chamber whichcooperates with the port 9, and a port 25 which cooperates with the portI I. There is like-. wise a port 26 cooperating with the port l3. Whenthe ports are in the position shown in Fig. 2, the ports I3 and 26 arein alinement, and therefore, the chamber 23 in the member 22 isconnected to the pipe 36 leading to the muflier I. At this. time thereis a' port 21 in alinement with a port 28, both of which are inalinement with the .pipe 4, and thus the chamber l is connected throughthese ports with the chamber 23 and to the atmosphere. This provides ameans whereby the control valve when inthe position shown in Fig. 2,isclosed to the vacuum creating means and the chamber I is fully openedand vented to the atmosphere. Such a condition is desirable when themethod of creating a vacilum is applied-to the control of a brakingmember for a rotating part.

The cylindricalmember 22 carries an arm 29 through which a pin 30passes. When the sleeve is shifted, the end of the sleeve engages thepin 30 and will shift the cylindrical member .22 with the sleeve. Thiscylindrical member is frictionally held in a set position by means of afriction clamping collar 3|. The 'member 22 extends beyond theright-hand end of the sleeve and is from the casing to the leading fromthe casing provided with a flanged member 32 whichhas a tapered openingtherethrough. .A metering pin 33 with a similar taper extends intothisopening. 5 This metering pin is carried by a lever 34 pivoted at 35.The lever has a forked end straddling a pin ll carried by the meteringpin 33. A spring 311s located between the inner side of the lever. 34and a-shoulder on the metering pin and this provides a means whereby thespring yieldingly forcest'he metering pin' against its seat in the I.Within the casing 3 recess vanishing at member32. Nuts 38 cause theleverwhen moved outwardly at its lower end to move thev 'metering pin 33away from the member 32-, thus providing, '55

2' I an opening as shown in Fig. 3 the drawing. The lever is controlledby a cam block 39 provided with a cam'groove 40 in which a pin 4|carried by the leverv moves. When the member 22 is moved from the leftas viewed in Fig. 2, to the position shown in Fig. 3, then the lever isswung on its pivot so as to move the metering pin 33 outward relative tothe seating member 32 'and thus providing an Opening to the atmosphereleading to the chamber 23.

When the valve is shifted to the position shown in Fig. 3, and is fixedin this position, the recess i0 is moved underneath the port with whichthe pipe is connected and the chamber 23 is, therefore, in communicationwith the vacuum creating means or the chamber 2. It is, however, a.throttled control, and not a wide open connection of the port -9. Atthis time, the recess I2 is also communicating with the pipe d, and thechamber i has a throttled connection with the chamber 23 of a charactersimilar to the throttled connection between the chamber and the vacuumcreating means. From certain aspects of the invention, the port leadingto the chamber i may be wide open,'but it is essential that the portleading to the vacuum creating means shall order that this vacuum on thechamber l'may be maintained at four inches and not built up, themetering pin has been shifted so as to open or vent the chamber 23 tothe atmosphere. The

shifting of the valve closes the port leading to I the pipe 6, so thatall connection to the atmosphere through the muiiler has been cut off.With this setting 'of the valve, there is just suflicient air admittedto the chamber 23 through the opening controlled by the metering pin '33to maintain the vacuum pull on the chamber 1 constant, provided the pullof the vacuum creatingmeans is constant. If there is a slight variationin the vacuum pull of the vacuum creating means, then there will be alike change in the degree of vacuum developed on the chamber I. In otherwords, the ratio of the vacuum on the chamber l to that on the chamber 2willv be maintained constant for a given setting 01' the valve. The camgroove ll is shaped so as to proportion the venting of the chamber 23 tothe vacuum pull of the vacuum creating means for accomplishing theresults stated; The block 29 may be shifted so as to varythe' timing ofthe shifting of the meteringpin 33 relative to the opening of thecontrol port leading to the vacuum creating apparatus.- The pipe I maylead to several chambers with which. it is desired to maintain a vacuumof substantially a predetermined degree. "Ihese chambers may beconnected to various types of deviceson which it is" desired to create avacuum, and the apparatus can be readily adjusted tothe system w'wmcn itis to be applied so as to maintain on said cham--- ber l a substantiallyconstant vacuum, varying only to the extent of the variation of thedegree of vacuum developedby the vacuum. creating means. Furthermore,the vacuum on the chamber may be regulated at will by a shifting of the2,061,488 c I v v valve. When it is desired to lower the degree ofvacuum on the chamber I relative to thaton the chamber 2, this can beaccomplished by the shifting of the sleeve to the right, and thusclosing partially the port leading to the vacuum creating means. .Theshifting of the valve does not shift the member 22 until the pin engagesthe end of the slot 42. The further shifting of the sleeve will, ofcourse, shift the member 22 and partiallyclose the metering Din, Thus itis that the chamber 1 may have the degree of vacuum thereon adjustedwithout opening the chamber to the atmosphere. This is particularlyuseful in the application of the method to the braking ofa rotatingpart, as the wheels of an automobile, as it permits the vacuumpull-exerted on the brake chambers to be increased or decreased at will,without completely releasing the vacuum pull on the brake chambers.

From the above it will be apparent that I have provided a method ofcreatinga vacuum-on a chamber which is of less degree than the vacuumcreating means operating thereon, and of maintaining said vacuum on thechamber of lesser degree for any desired length of time. In order toaccomplish this, an intermediate control chamber is provided which isindependently connected to the chamber on which the vacuum is to bedrawn and the vacuum creating means. This chamber is also connected tothe atmosphere and there are control valves so that the volume of airdrawn from the control chamber for a given period of time may bedecreased by the closing ofi of the valve between said chamber and thevacuum creating means. At the same time, the volume ofair drawn from thechamher on which the vacuum is to be created into the control chamber issimilarly varied. The vent leading to the atmosphere is inverselyvaried, so that when the volume of air drawn from the control chamber bythe vacuum. creating means is decreased, the volume of air from theatmosphere drawn into the chamber is increased, and thus byproportioning the amount of air drawn from the control chamber and fedto the control chamber, a vacuum of a predetermined j degree, less thanthat of the vacuum creating means can be obtained and maintained on thiscontrol chamber, and likewise on the larger chamber 'on which it isdesired to. create a vacuum. Then again. whenthe volume of air drawnfrom the control chamber is. increased for a given period of time by theopening of the passage leading to the vacuum creating means, the volumeof air drawn in through the vent in the same period vof time-will bedecreased, and thus it is by controlling these portsleading to theatmos-' phere and leading to the vacuum creating means, any desireddegree otvacuum within the limits of the vacuum creating means may beselected and maintained. a

In my co-pending application Serial No.

597,358, filed or even date herewith, and patented novemberfzs, 1933,No. 1,937,444, the apparatus described in detailjs shown, described .andclaimed as applied to the braking of a rotating element, and no claim tothis apparatus isomade in this application.v It. will be understood thatthe method,- described and claimed may be carried out'by mechanisms 01'entirely diflerent' construction from that shown andv described.".-,

Having thus described the invention, what I claim as new anddesirc tosecure by-Letters Patent, is-

1. The method of creating and maintaining a vacuum on a chamber of lessdegree than the vacuum creating means operating thereon, consisting inconnecting said chamber and said vacuum creating means to a controlchamber, varying the volume of air drawn from said control chamber in agiven period of time,venting said control chamber to the atmosphere andinversely varying the amount of air drawn from the atmosphere into saidcontrol chamber in the same period whereby the degree of vacuum createdon said control chamber may be changed to a predetermineddesired degreewithin the limits of the vacuum creating means and maintained.

2. The method or creating and maintaining a vacuum on a chamber of lessdegree than the vacuum creating means operating thereon, consisting inindependently connecting said chamher and said vacuum creating means toa control chamber, coordinately controlling the passages leading,respectively, to the vacuum creating means and the chamber on'which thevacuum is to be created, venting said control chamber to the atmosphereand inversely controlling the opening of the passage leading to theatmosphere during the closing of the passages leading to the vacuumcreating means and the chamher on which the vacuum is to be created.

FREDERICK L. SHELOR.

